This invention is generally related to an external shield for use in optoelectronic ports, and more particularly related to shields that prevent electromagnetic emissions from optical fiber link modules.
Optical fiber is widely used to rapidly and reliably transfer data between computer systems. In general, an optical fiber includes a core region that is coated by an annular clad. The core region has an index of refraction greater than that of the clad, so that light is transmitted through the core by total internal refraction. Optical fibers transmit data from an optoelectronic transducer, such as a laser or Light Emitting Diode (LED), to an optoelectronic receiver that generates electrical information based upon the signal received.
Optical transceivers tend to generate electromagnetic interference (EMI) in the range of about 100 megahertz to 5 gigahertz, and this radiation is most likely to escape from the point at which the fiber is connected to the optoelectronic component. The fibers are typically either threaded onto the optoelectronic components or latched by the use of connectors such MTP (Multicast Transport Protocol) or MTO (Multi-Modal Transport Operator) connectors. Because these connectors are typically plastic, however, they are not effective EMI shields. In order to limit EMI, external shielding has therefore been provided in various forms. These shields have an opening that allows the connector to attach to the optoelectronic component. This opening is in effect an electromagnetic hole in the shield that allows EMI to escape.
The present invention is an optical fiber link module comprising upper and lower portions and a shield. One of the upper portion or lower portion has a groove, and one of the upper portion or lower portion has at least one tab extending therefrom. The shield has a detent and at least one cutout. The detent engages the groove, and the at least one cutout cooperates with the at least one tab.
It is an object of the present invention to provide an optical fiber link module of the type described above that inhibits EMI.
Another object of the present invention is to provide an optical link module of the type described above that permits easy access to the connector and fiber cable by the end user.
Still another object of the present invention is to provide an optical link module of the type described above that is cost effective.